Automatic telephone exchange



June 13, 1933- I s UNDBERG 1,914,030

AUTOMATIC TELEPHONE EXCHANGE Filed Ma ch 10, 1951 v v /YeA/T pg y" 1 Patented June 13, 1933 UNITED STATES PATENT OFFICE SVEN EDVARD LINDBERG, OF STOCKHOL'MI, SWEDEN, ASSIGNOR T0 TELEFONAKT'IE- BOL AGET L. M. ERICSSON, OF STOCKHOLM, SWEDEN, A COMPANY OF SWEDEN AUTOMATIC TELEPHONE EXCHANGE Application filed March 10, 1931, Serial No. 521,529, and in Sweden March 15, 1930.

The present invention relates to machine driven automatic telephone exchanges and has for its object to bring about as far as possible a uniform manufacture of such telephone exchanges. It is previously known to divide the subscribers for this purpose in equally large groups and to distribute the different apparatus of the automatic exchange over a corresponding number of uniformly equipped frame sections, each of which is provided with a complete set of selectors with appertaining driving motor and other switching members for establishing talking connections within the same group of subscribers, as well as with group selectors for establishing connections between the dif ferent groups of subscribers. This division of the exchange into a number of parts or sections, which are uniform from the point of view of manufacture, has hitherto not comprised the apparatus serving to produce the different signalling currents, which apparatus have been common to the whole automatic exchange. According to the present invention also this signalling equipment is divided into a plurality of uniform aggregates, one such individual signalling aggregate being allotted to each group of subscribers and adapted to supply the signalling currents required in service, such as alternating currents of difierent kinds for calling, testing, etc. Said distribution of signalling equipment to the different groups of subscribers has the advantage that each group of subscribers with the appertaining selectors,

etc. will comprise a self-contained automatic.

telephone exchange. This results in increased safety of operation and in a possibility of completely standardizing the manufacture. The increase in cost that would be caused by such a decentralization of the signalling equipment is compensated according to the present invention thereby, that the selector driving motor appertaining to each group of subscribers also serves as a driving motor for the signalling equipment. The signalling equipment most commonly used comprises a motor generator and an interrupter for producing intermittent signalling current, said interrupter being driven by the subscribers numbers. An increase over and aggregate is used the driving motor of the generator is thus according to the invention constituted by the driving motor of the selectors. The electric generator may, if desired, be entirely dispensed with if the motori's provided instead :with means for tapping signalling alternating currents from the windings of themotor in a manner known per se.

The invention is illustrated on the accompanymg drawing. Figure 1 is a front view, Figure 2 a side view and Figure 3 a plan view of a frame section comprising all selectors and other apparatus appertaining to one group of subscribers in an automatic exchange having machine driven selectors.

The frame section is composed of a plurality of elementary frames A, B, O, D, E, of which the first, A, carries line and cut off relays and other apparatus appertaining to the subscribers lines. The elementary frames B, C, D are selector frames for, by way of example, call finders, first group selectors and final selectors respectively. The elementary frame E carries registers, signalling means and other auxiliary apparatus appertaining to the frame section. The selectors, which are not shown on the drawing, are in this example of the type in which the contact arms are adapted to move in two directions in one and the same horizontal plane and in which the contact fields are composed of vertically extending blank wires supported by brackets F. In the example shown on the drawing each elementary frame is adapted to support such selectors disposed one above the other, the relays or other auxiliary apparatus G being disposed laterally of the appertaining selector. If each selector has a capacity of 500 lines each frame section may serve a group of 500 subscribers and the exchange in its entirety may with one group selector for 20 groups obtain a maximum capacity of 10,000 subscribers numbers. An increase over and above said capacity may be obtained in known 1 All selectors are driven from an electric motor H, individually allotted to the frame section, through the intermedium of a horizontal shaft I and a plurality of vertical shafts K which by means of bevel gears L are 5 connected to the horizontal shaft and to which the selectors may be connected in known manner by means of electromagnetic couplings.

According to the invention the same electric motor H is also adapted to drive an interrupter aggregate M which by means of gears N is connected to the horizontal shaft I and by means of which aggregate a continuous alternating current may be transformed to an intermittent signalling current in a manner known per se. In the shown example the signalling alternating current is in known man ner tapped off the armature winding of the motor or off another winding of the motor, no separate alternating current generator being thus required.

I claim 1. A telephone exchange system comprising a number of frames, selectors mounted on said frames, electrical motors individually allotted to said frames and adapted to drive the selectors of the appertaining frame, and signal current producing apparatus individually allotted to said frames and adapted to be driven by the selector motor of the appertaining frame.

2. A telephone exchange system comprising a number of subscribers groups, a corresponding number of frame sections each equipped with selectors and other apparatus for dealing with the traffic in the corresponding subscribers group, electrical motors, individually allotted to said frame sections and adapted to drive the selectors of the appertaining frame section, and signal current producing apparatus individually allotted to said frame sections and adapted to be driven by the selector motor of the appertaining frame section.

3. A telephone exchange system comprising f 5 a number of frames, selectors mounted on said frames, electrical motors individually allotted to said frames and adapted to drive the selectors of the appertaining frame, signal current producing apparatus individually 5 allotted to said frames and adapted to be driven by the selector motor of the appertaining frame, and means for generating alternating signalling currents including windings on the selector motors.

In testimony whereof I affix my signature.

SVEN EDVARD LINDBERG. 

